The earthquake, which struck at 1:25 p.m. local time on Friday, was centered about 112 miles (180 kilometers) northwest of Attu Island in Alaska, or 168 miles (270 kilometers) southeast of Bering Island in Russia. It struck at a depth of about 19 miles (31 kilometers), making it a shallow earthquake.

The U.S. National Tsunami Warning Center put the preliminary magnitude of the earthquake at 6.9. "Based on earthquake information and historic tsunami records, the earthquake is not expected to generate a tsunami," the center said.

Friday's earthquake is expected to have been felt across parts of the Aleutian Islands, but damage or casualties are unlikely. The closest islands - Attu Island and Bering Island - have only a small population. Attu Island is also home to Attu Station, which was closed in 2010.

The sparsely populated region of Alaska, which sits on the so-called 'Pacific Ring of Fire', is occasionally struck by powerful earthquakes. Most notably, an enormous 9.2-magnitude earthquake struck north of Prince William Sound in Alaska on March 27, 1964, unleashing a tsunami which killed at least 143 people.